A variety of catheters for delivering a therapy and/or monitoring a physiological condition have been implanted or proposed for implantation in patients. Catheters may deliver therapy to, and/or monitor conditions associated with, the heart, muscle, nerve, brain, stomach or other organs or tissue. Many catheters are tracked through the vasculature to locate a therapeutic or diagnostic portion of the catheter at a target site. Such catheters must have flexibility to navigate the twists and turns of the vasculature, sufficient stiffness in the proximal portion thereof to be pushed through the vasculature alone or over a guidewire or through a lumen, and the capability of orienting a distal portion thereof in alignment with an anatomical feature at the target site so that a diagnostic or therapeutic procedure can be completed. In general terms, the catheter body must also resist kinking and be capable of being advanced through access pathways that twist and turn, sometimes abruptly at acute angles.
For certain procedures, it may be necessary for the clinician to accurately steer or deflect the catheter so that a distal opening thereof may be aligned with an ostium of a branch or side vessel. The distal portions of catheters frequently need to be selectively curved or bent and straightened again while being advanced within the patient to steer the catheter distal end into a desired body lumen or chamber. For example, it may be necessary to direct the catheter distal end through tortuous anatomies and/or into a branch at a vessel bifurcation. In addition, some procedures require high accuracy in guidewire orientation. For example, often patient's arteries are irregularly shaped, highly tortuous and very narrow. The tortuous configuration of the arteries may present difficulties to a clinician in advancement of a catheter to a treatment site.
It is known to employ a pull wire connected to a distal portion of certain catheters and controlled by a proximal handle component. With such mechanisms, when the pull wire is pulled, the catheter is bent or deflected in the direction of the pulled wire. However, a need in the art still generally exists for improved apparatuses and methods for navigating through or within a patient's anatomy.